Medical Device Daily Associate
The FDA reported that it approved a new product designed to protect against leakage of cerebrospinal fluid (CSF) after brain surgery. And, according to the company which developed it, this is the "first and only product indicated as an adjunct to sutured dural repair during cranial surgery to achieve watertight closure."
The DuraSeal Dural Sealant System, made by privately held Confluent Surgical (Waltham, Massachusetts), is used in dura mater surgery and is applied over sutures to prevent CSF fluid from leaking out of the incision site. The dura mater is the tough, outermost, fibrous membrane that covers the brain and spinal cord, and lines the inner surface of the skull.
Leakage of CSF can lead to serious complications, such as severe headaches, infection and meningitis.
The company received a recommendation of approval this past December from the Neurological Devices Panel of the FDA's Medical Devices Advisory Committee, though the panel's vote appeared to be a very cautious thumbs-up (Medical Device Daily, Dec. 2, 2004).
While a clear majority of panel members – 7 to 2 – voted to recommend approval of the device, they recommended roughly eight conditions. Some of the conditions included post-marketing surveillance of infection rates following DuraSeal procedures, labeling changes warning against the risk on infection, more precise labeling for the product's intended use and patient population clarification.
The product received the CE mark in 2003 (MDD, June 26, 2003)
While the panel and the agency may have had some reservations about the product, both noted how closely Confluent consulted with the FDA regarding its clinical trial design. The FDA also acknowledged during that panel meeting that the company had made an "impressive" effort to consult the agency and get feedback on the trial process.
"This product is unique because it is the first device specifically designed and studied to seal sutured dura mater incisions," said Daniel Schultz, MD, director of FDA's Center for Devices and Radiological Health (CDRH) in a statement.
Presently, the FDA noted, surgeons use a variety of approaches to make sure the surgical incision site doesn't leak spinal fluid. One method is to "oversew" the area, which means surgeons sew the stitches closer together in the tissues immediately overlying the surgical site. Some surgeons pack the area with other tissues from the patient, such as fat, muscle, or connective tissue.
DuraSeal was evaluated in 111 patients. The study involved were 10 hospitals in the U.S. and one in Europe. All of the patients treated with DuraSeal showed no CSF leakage during the intra-operative assessment. The adverse events observed were consistent with the type and complexity of the surgery performed, and with the patients' medical conditions, the company said. Nine of the patients (8.1%) had a post-operative infection at the surgical site.
DuraSeal consists of synthetic absorbable sealant materials and a dual syringe applicator to apply the sealant to the incision site. The sealant is composed of two solutions, a polyethylene glycol ester solution and a trilysine amine solution. When mixed together, the solutions combine to form the sealant gel. The sealant is absorbed in about four to eight weeks, enough time to allow for healing.
Importantly, the device can be stored at room temperature and prepared in less than two minutes. When sprayed on to the dura, a strong, adherent sealing layer is produced and effectively seals the suture line within seconds.
A feature unique to the DuraSeal Sealant is the blue colorant that provides the surgeon what the company said is "excellent visualization" of coverage and thickness of the material upon application to the dura, according to Confluent.
The clinical results presented to the FDA demonstrated the DuraSeal Sealant was able to achieve watertight closure in 98% of cases, immediate sealing was obtained on the first application in 95% of cases, and 95% of applications were rated as "easy" to "very easy" by neurosurgeons using the product.
"Watertight closure of the dura has to date been an elusive goal," said Harry van Loveren, MD, chairman of the Department of Neurosurgery, University of South Florida (Tampa), and a principal investigator in the pivotal DuraSeal multi-center study. "With DuraSeal," he added, "it can become a reality." He also said that the new sealant has the potential for providing "a new paradigm for how the dura is closed following cranial surgery."
The company noted that there are about 250,000 craniotomies performed in the U.S. each year and that almost all cases involve a suture repair of the dura.
Confluent said it has established an "extensive and distinguished" neurosurgeon-focused distribution channel to represent the DuraSeal product in the U.S. market.
The company will also have the funds to market the product, having received a $23 million Series D round of venture funding at the beginning of the month (MDD, April 1, 2005).
Confluent's other products include the SprayGel Adhesion Barrier System for prevention of adhesions in abdominal and pelvic surgery. The company also is developing surgical sealing and adhesion barrier products for spine and orthopedic surgeries.